Internal-combustion engine



1,615,282 25 1927' 0. E. JORGENSEN INTERNAL COMBUSTIQN ENGINE Filed Feb.16. 1922 4 Sheetrs-Sheet l vwamfoz @51 flame/1 0 W- ae/$04 n. 25 1927-Ja O. E. JORGENSEN INTERNAL (TYNCUSTIQN ENGINE 4 Sheeis-Sheec 2 '1 ledFeb. 16 192? 1,615,282 25 1927' o. E, JofiGENsEN INTERNAL COMBUSTLONENGINE Filed Feb. 16, 1922 4 Sheets$heet 3 -49 M. [an E 57 q I m if 1 6g I 4 F L if i F J *1 QNQ Q 5919 MW 5 Patented Jan. 25, 1927.

UNITED STATES PATENT OFFICE.

OLAV ESKIL J'ORGENSEN, 0F FOREST HILLS, NEW YORK,

ASSIGNOR TO WORTHING- TON PUMP AND MACHINERY CORPORATION, OF NEW YORK,N. Y., A CORPORATION OF VIRGINIA.

INTERN All-COMBUSTION ENGINE.

Application .Lled February 16, 1922.

The present invention relates to improvements in internal combustionengines, and particularly to engines of the Diesel type.

The object of the invention is to provide a durable and etlicientdouble-acting engine of the two cycle'Diesel type in a compact formparticularly suitable for heavy power purposes, as, for example, formarine engines, the construction being such that the various parts ofthe engine may be readily disassembled and re-assembled.

WVith these general objects in view, the invention consists in thefeatures, details of construction and combination of parts which willfirst be described in connection with the accompanying drawings and thenparticularly pointed out in the claims.

In the drawing,-

Fig. 1 is a vertical section, partly in elevation, on an enlarged scalethrough the center of an engine cylinder embodying certain features ofmy invention;

Fig. 2 is an enlarged sectional view of the piston with parts of thecylinder;

Fig. 3 is a horizontal section on the line 3-'3 of Fig. 2;

Fig. 4 is a horizontal section on the line 4-4 of Fig. 2;

Fig- 5 is a horizontal section on the line 5-5 of Fig. 1,-

Fig. 6 is a diagrammatic side elevation of the upper part of an enginecomprising several engine units and ascavenging air pump embodying myinvention;

Fig. 7 is a, detail plan view of the valve mechanism at the upper end ofthe engine, shown in Fig. 1;

Fig. 8 is a horizontal rod;

Fig. 9 is a diagrammatic transverse sectional view showing thescavenging air pump; and

Figs. 10 and 11 are enlarged sectional views showing the air pump.

Referring to the drawings, A, Fig. 6, indicates the frame of the engine,and B the cylinder base which is supported by the frame and is the solemeans for supporting the upper and lower cylinders respectively of theengine. This cylinder base has channels, chambers or passages, some ofwhich serve as the exhaust ports and others as the section of the pistonSerial No. 537.136.

inder base has a diaphragm, as indicated at b, Fig. 1, which separatesthe upper and lower sets of ports from each other.

The cylinders are each formed with an enlarged wall at one end, theupper cylinder having this enlargement at the lower end and the lowercylinder having the enlargement at the upper end. These enlargedportions are cylindrical and fit into corresponding openings in thecylinder base. In the best embodiment of the invention, each cylindercomprises a plurality of parts, in the present example two parts, anouter member 1 and an inner member or cylinder liner 2.

In the best embodiment of the invention the liner 2 extends beyond thecorresponding outer member 1 at one end and the liner and its outermember are flanged, as shown at 3 and 4 respectively, to form theenlarged diameter of the cylinder.

Eachliner has itsenlarged end inserted in a corresponding recess in thediaphragm and is provided on one side with inlet ports for scavengingair, as indicated at 5, and on the other side with exhaust ports 6. Eachcylinder is held to the cylinder base by suitable means. In the best.embodiment of the invention, the clamping means comprises a clampingring, as indicated at D, D, secured to the cylinder base by stud bolts?and nuts 8. Each clamping ringhas one inner edge coned or chamfered tobear against the corresponding, coned or chamfered edge of the flange ofthe respective outer member 1. By removing the nuts 8, the cylinder isreleased and may be removed from the cylinder base. When in place it isheld tightly to the cylinder base by the clamping rin and nuts.

The cylin ers are provided with water jackets, indicated at C, C,respectively.

inlet ports for the scavenging air. The cyl- Each jackethas one endarranged to enter a counterbore in the clamping ring-and to make awater-tight joint therewith. To insure this under all conditions, apacking ring may be inserted between the end of the jacket and theclamping ring, as indicated at 9. The packing ring may be inserted in acounterbore in the end of the jacket, as will be clear from Fig. 1. Thejacket is held in place by suitable means. In the best embodiment of theinvention, the jacket is held in place by its cylinder, only, so thatwhen the cylinder is released from the cylinder base, the cylinder andits water jacket may be removed as a unit. In order to accomplish thisresult, the cylinder has a screw threaded boss to which is screwed athimble 10, 11 having an outwardly extending flange counterbored at thecorner, as shown in Fig. 1, and the jacket has an inward extendingflange arranged to enter the counterbore. Suitable stud-bolts and nutsserve to secure the jacket to the thimble.

The thimble 10 for the upper cylinder is arranged to receive acylindrical block 12 carrying suitable poppet valve mechanismhereinafter more fully described. The thimble 11 for the lower cylinder,serves as the packing-chamber to receive the pistonrod packing, notshown. This packing, when in place, may be tightened by a stuffing boxgland 13 held in lace by bolts 13 which extend through the ange of thewater jacket and are screwed into the flange of the lower thimble.

The lower jacket E, Fig. 6, is provided with a boss 14 to receive acircular block 15 which carries the valve device for supplying fuel tothe lower cylinder. The circular block 15 has a cylindrical projection16 which fits into a recess in a boss 17 formed on the lower cylinder.

In the best embodiment of the invention the ends of the cylinders are ofa novel construction which gives great strength with relatively lightweight. In this construction, the cylinder end where the thimble 10 or11 is screwed to it, is made thick enough to form a substantial ring ofmetal which will successfully resist any stresses to which it may besubjected. The Wall of the cylinder end from the ring toward thecylindrical portion constituting the main body of the cylinder,comprises two zones, viz, a conical zone and a spherical-zone, thelatter being next to the cylinder body, while the conical zone joins thespherical zone to the ring. In the best embodiment of the invention theconical portion is tangential to the spherical portion, and, while inpractice a small deviation from this ideal is not a serious objection,the more nearly the approach to the ideal condition, the lighter thewall may be for the same strength.

While the piston may be of any suitable construction, the presentinvention includes a new type of piston particularly coacting with thecylinder. This piston has one end domed as indicated at 18, Figs. 1 and2, to enter the corresponding end of the cylinder and nearly but notquite fill the space therein, only a small amount of clearance beingleft therein, say. for example, from about 5 to 7 per cent. The crankend 19 of the piston must be of such exterior configuration as to reducethe final or minimum clearance to a relative amount suitable in enginesof this type, while locating it so that the fuel valves may dischargeinto it at the proper time. This is accomplished in the present exampleby forming this end of the piston so that its portion next to thepiston-rod is substantially cylindrical in cross-section, while theintermediate portion is substantially elliptical in cross-section, asshown in Fig. 4. In this way a space is left on each side of the pistonopposite the fuel injection nozzles. From this elliptical portion thepiston-end 19 flares outward to the full diameter of the piston body.

In the best embodiment of the invention, the piston and piston rod arespecially constructed to provide a durable, readily assembled device.The piston-rod 2U is formed with an enlarged end 21 having a flange 22,while near the other end of the piston the rod has an intermediateflange 23 below which is an enlargement 24 providing a shoulder.

The piston-wall comprises two cylindrical body portions, 25 and 26, eachprovided with a series of grooves for the packing rings 27.

These two cylindrical portions have their adjacent ends somewhat reducedin diameter, the reduced portions being received within thecorresponding circular portions or rings of an intermediate split ringmember 28 formed of three sections joined by bolts and nuts passingthrough radially extending flanges 29 formed on flat webs 30, extendinglike chords of the circumference of the piston, as will be clear fromFig. 3.

The intermediate member is locked to the lower cylindrical portion 26 ofthe piston wall, in any suitable way, as, for example, by providing theintermediate split-ring member with an inward extending circumferentialrib 31 extending into a circumferential groove in the outer surface ofthe lower cylindrical portion, as will be clear from Fig. 2. The uppercylindrical portion 25 is not locked to the intermediate portion but isleft free to expand and contract, the joint between the two being,however, a water tight sliding connection. The up er cylindrical bodyportion 25 is provided elow its upper end with an inward extendin flange32 which rests on the flange 22 at the upper end of the piston-rod, andagainst which rests the upper dome-shaped piston end 18, suitablemachine screws 33 holding the parts together,.as shown in Fig. 2. Thelower cylindrical body portion 26 is provided with an inward extendingflange 34 making a tight fit with the outer surface of the intermediateflange 23 of the piston rod. The lower piston end 19 fits against thelower surface of said flange 34 and is held to the flange by machinescrews 35. Suitable long machine screws 36 pass through the intermediateflange 23 and are threaded into the lower piston end portion 19.

In an engine of this type it is important to provide water circulationforcooling the piston heads or end portions and this may be done, asshown in Fig. 2, by making the piston rod 20 hollow or tubular andinsertmg within it a water pipe, as indicated at 37, whose exteriordiameter is less than the interior diameter of the rod, so as to leavean annular water space around the pipe. To the pipe 37 is secured acollar 38 forming a baflle or diaphragm; The piston rod has waterpassages, above and below the collar 38, as indicated at 39 and 40,these connecting the space inside the lower piston end 19 with theannular space of the piston rod. The water pipe 37' has a collar 41secured to it near its upper end, this collar being provided with holes42 for the passage of water. A bushing 43 threaded into the piston rodis provided with an inturned flange which laps over the collar 41. Whilethe water may flow up through the water pipe and thence down through theannular passage, it will be advantageous to allow the cooling water toflow up the annular passage and thence down and out through the Waterpipe, because in this way the coldest water will be next to the pistonrod. The water may be admitted to the moving piston-rod, and dischargedtherefrom in any suitable way, as, for example, by any of the meansalready well known in the art.

In order to assist in maintaining a water tight joint at thecircumference of the intermediate fla-nge 23, the piston-rod peripheryof this flange is provided with a .groove into which may be cast asuitable alloy through a notch provided for that .purpose. The alloyinthe groove is indicated at 44, Fig. 2, and the notch,also filled withalloy, is indicated at 45.

The collars 38 and 41 are secured to the wateriipe 37 by electricwelding,.as is indicate by the solid block in Fig. 2.

It will be obvious that by the construction of the piston as described,a light yet strong piston is produced, which may be readily assembledand disassembled. Also, the longitudinal expansion and contraction ofthe piston due to temperature changes is provided for.

The valve mechanism at the upper end of the cylindercomprises anair-starting valve and a fuel valve, with valve operating devices bywhich, at starting, the air valve may be operated with proper timing,and so soon as the engine is operating properly the air-starting valvemay be cut out of operating and the fuel valve put in action.

The air-starting valve is an ordinary poppet valve, opening inward, asindicated at 46, Fig. 1. It is yieldingly held shut by a shown. The

spring 47 and its spindle projects outward 'moving part of the engine,not shown. The

rocker-arm 50 carries a fulcrum 52 at its free end on which is journaledan adjustable trip-arm 53 having one end provided with a screw 54 which,under certain conditions, will strike the free end of the starting-airvalve spindle 48 and thus force the valve open. The other end of thetrip-arm 53 is pivotally connected to the end of an eccentric rod 55arranged to be adjusted by an eccentric 56 fixed on an eccentric shaft57. This eccentric shaft is provided, with a handle 57, shown in Fig. 7,by which its eccentric may be rotated to adjust it. The pivot whichconnects the trip arm to its eccentric rod has-its axis coincident withthe axis of the fulcrum of the rocker-arm 5O when'the correspondingecentric, is in such a position as to hold-the trip arm out ofengagement with the starting air-valve.

The fuel valve 58 is also of the poppet type normall ClOL'Gd. by aspring 59 and having its spindle arranged to be struck by the end of ascrew 60 carried by the triparm 53. When the trip-arm is out of actionon the starting air-valve 46, it is in action on the fuel valve, andvice-versa, this being determined by the position of the eccentric 56.

With a plurality of engine-units, one or more cylinders may be suppliedwith start ing air to start all the engines, the other cylindersreceiving fuel at the proper time. As soon as the engines are. turningunder the pressure of the combustion gases in some cylinders, theeccentric or eccentrics 56 may be turned over so as to shift thetrip-armor trip-armsv and cut out the starting-air mechanism, therebycutting in the fuel valves for those cylinders.

The lower cylinders are notarranged for the use of starting-air but haveonly fuel valves of the poppet-valve type, as shown at 61, each beingoperated by a rocker 62 secured on a rocker arm 63 oscillated by a rod64 from a moving part of the engine, not poppet-valve is held closed bya spring 65.

The fuel valves illustrated for the upper and lower cylinders are of anysuitable type inwhich the oil is blown in by injection air. As valves ofthis type are well known no specific description of the same isrequired.

An important feature of the power plant here set forth comprises animproved arrangement of a plurality of double-acting engines of theDiesel type on a cylinder base in the manner described, with ascavenging air pump. Such an arrangement is shown in Fig. 6 in which E,E are the air-pump cylinders. The general arrangement of the airpumpwill be clear from Figs. 9, 10 and 11, the air pump being shown as ofthe type described and claimed in my Letters Patent No. 1,447,514, datedMarch 6, 1923.

Referring to Fig. 11, E is the cylinder of the upper air-pump, and E,the cylinder of the lower air-pump. F is the upper piston, F, the lowerpiston, and G the piston rod connected to both pistons. H is the uppercylinder head, H, the lower cylinder head and H an intermediate headcommon to both cylinders.

The intermediate head H is flanged and is fitted into a seat formed in a.septum or horizontal partition a. Fig. 10, which constitutes a part ofthe cylinder base B, the partition 11 having a horizontal flange a, anda vertical annular flange (1 at the seat. The intermediate head H issecured in its seat in an suitable way as, for example, by machinescrews 1 which are accessible from the upper side of the cylinder basewhen the upper air pump is removed.

The upper cylinder E provided with a supporting member having acylindrical hub-portion 6, Fig. 10, arranged to enter a correspondinghole in the upper member or plate a of the cylinder base and having aflange 6,, overhanging said platea,, to which it may be secured in anysuitable way, as, for example, by machine screws, as indicated at m,Fig. 11. The cylinder E is otsuch length that its lower end reachesnearly but not quite to the upper surface of the intermediate head Hwhereby a suitable passage or port for the entrance and discharge of airbeneath the upper piston F is provided all around the cylinder, thisopening leading into an upper chamber or space I formed in the cylinderbase above the septum a. The lower cylinder is similarly constructedand. mounted in the cylinder base, being inserted into the cylinder basefrom below upward and held in place by the machine screws 3. Its upperedge extends nearly but not quite to the lower surface of theintermediate head H so as to leave an air assage or port all around thecylinder where y the space in the lower cylinder above the piston F, isput in communication with a lower chamber or space 1,, Fig. 10, formedin the cylinder base below the septum a.

The side walls of the cylinder base are provided with openings leadingfrom the upper and lower chambers I, 1,, respectively, to a suctionvalve chest K, and corresponding openings leading to' a discharge valvechest K,. These valve chests are secured to opposite sides of thecylinder base and each has two sets of valves. The 0t suction valves areindicated at L,, L, and the sets of discharge valves at M,, Mrespectively. \Vhile any suitable valves may be employed, thoseindicated are of the plate spring variety, for example, such as arefully disclosed in Patent No. 1,341,145, dated May 25, 1920.

The upper end of the cylinder E is connected by a suitable passage Nwith the chamber I, below the diaphragm a, the passage N opening intothe top of the cylinder, as will be clear from Fig. 11. The lower end ofthe cylinder E, is connected, by a passage N,, with the chamber I abovethe diaphragm a, the passage N, opening into the bottom of the cylinderE,, as will be understood t'rom Fig. 11. Each passage N or N, is formedpartly in its own cylinder, and partly in the cylinder base B, as shownin Fig. 11. The part of each passage within the cylinder base isenclosed by a wall a.

The piston rod (iv is reciprocated in any suitable way from the mainshaft D, as, for example, through a crank 0, connecting rod 1, andcross-head Q1 running in guides B.

By this combination a large yet short conduit S may be carried closelyalongside the cylinder base to supply scavenging air to each engine inits turn, the engines of course having their cranks set at angles to oneanother so that the working strokes of the engines will occur in thedesired timed relation.

By this arrangement oi the engines and the-scavenging air-pumps, anyengine or the air-pump may be dismantled more readily than hasheretofore been possible and with the removal of a minimum of parts,but, also, there is less loss by friction in the How of air to theengines from the pump and hence a greater relative eiliciency.

While.in the foregoing specification, the invention has been moreparticularly shown and described as embodied in a vertical engine, it isto be understood that the invention is applicable to horizontal orinclined engines, and that the terms upper and lower referring to thecylinders, are to be understood as including cylinders which are notabove and below each other, but nearest to or farthest from the crankshaft.

What is claimed is:

1. In an internal combustion engine, the combination, with a cylinderbase having a vertical bore and having scavenging air inlet passages andexhaust passages, of a crank shaft, a cylinder projecting into the saidvertical bore and provided with inlet and exhaust ports in communicationwith the corresponding passages of the cylinder base, said cylinderbeing detachably secured to the cylinder base on the side awa from thecrank shaft and having its com ustion chamber portion above the cylinderbase, a piston movable in the cylinder, and means for driving the crankshaft from said piston.

2. in an internal combustion engine, the combination, with a cylinderbase having a vertical bore and inlet and exhaust passages,

of a crank shaft, a cylinder detachably secured to the cylinder base onthe side away from the crank shaft, said cylinder comprising an outermember and a liner, the latter extending beyond the outer member andhaving inlet and exhaust ports communicating with the correspondinginlet and exhaust passages of the cylinder base, a piston movable in thecylinder, and means for driving the crank-shaft from the engine. V

3. In an internal combustion engine, the con'ibination, with a cylinderbase having a vertical bore, and having scavenging air inlet passagesand exhaust passages, of a crank shaft, a cylinder projecting into thesaid vertical bore and provided with inlet and exhaust ports incommunication with the corresponding passages of the cylinder base, saidcylinder being detachably secured to the cylinder base on the side awayfrom the crank shaft and having its combustion chamber portion above thecylinder base, a water-jacket for said cylinder, said waterjacket beingfastened only to the outer end of the cylinder, whereby upon removal ofthe cylinder from the cylinder base the waterjacket also is removed with,it, a piston movable in the cylinder, and means for driving the crankshaft from said piston.

4. In an internal combustion engine, the combination, with a cylinderbase having a vertical bore and having scavenging air inlet passages andexhaust passages, of a pair of cylinders projecting into the saidvertical bore from opposite sides ofthe cylinder base, each cylinderbeing provided with inlet and exhaust ports in communication with thecorresponding passages of the cylinder base, said cylinders beingdetachably secured to the cylinder base, one cylinder having itscombustion chamber portion above the cylinder base and the other havingits combus tion chamber portion below the cylinder base, and a pistonarranged to work in both cylinders.

5. In an internal combustion engine, the combination, with a cylinderbase having a vertical bore, and havlng scavenging air inlet passagesand exhaust passages, of a pair of cylinders projecting into the saidvertical bore from opposite sides of the cylinder base, each cylindercomprisingan outer member and a liner, ,the latter extending beyond theouter member and having inlet and exhaust ports in communication withthe corresponding passages of the cylinder base, said cylinders beingdetachably secured to thecylinder base, one cylinder having itscombustion chamber portion above the cyl inder base and the other havingits com bustion chamber portion below the cylinder base, and a pistonarranged to work in both cylinders.

6. In an internal combustion engine, the combination, with a cylinderbase having a vertical bore, and having scavenging air inlet passagesand exhaust passages, of a palr of cylinders projecting into the saidvertical bore from opposite sides of the cylinder base, each cylindercomprising an outer member and a liner, the latter extending beinderbase and the other having its combustion chamber portion below thecylinder base, a water jacket for each cylinder, each water jacket beingfastened only to the outer end of its cylinder, whereby upon removal ofa cylinder from the cylinder-base its water jacket also. is removed withit, and a piston arranged to Work in both cylinders.

7. In an internal combustion engine, the combination, with a cylinderbase having a vertical bore and having an intermediate diaphragmprovided with an opening, of a pair of cylinders arranged on oppositesides of the cylinder base, each cylinder having an end portionprojecting into the vertical bore and contacting with the diaphragm, aclamping ring for each cylinder, said rin being arranged on oppositesides of the cylinder base, and means for detachably securing eachclamping ring to the cylinder base to hold its respective cylinder inplace.

8. In an internal combustion engine, the combination, with a cylinderbase having a vertical bore and having an intermediate diaphragmprovided with an opening, of a pair of cylinders arranged on oppositesides of the cylinder base, each cylinder having an end ortionprojecting into the vertical bore and contacting with the diaphragm, aclamping ring for each cylinder, said rings being arranged on oppositesides of the cylinder base, means for detachably securing each clampingring to the cylinder base to hold its respective cylinder in place, anda water jacket for each cylinder, each jacket being detachably securedonly to the outer end of its respective cylinder and being arranged tohave a slidable water-tight connection with its respective clampingring.

9. In an internal combustion engine, the combination, with a cylinderbase having a vertical bore and a diaphragm provided with an opening, apair of cylinders arranged on opposite sides of the cylinder base, eachhaving an end projecting into the vertical bore and making contact withthe diaphragm, a clamping ring .for each cylinder, said rings beingarranged on op osite sides of the cylinder base, each ring having acounter-bore in its outer face, and means for detachably securing eachring to the cylinder base to holdv the cylinders in place, of a waterjacket for each cylinder, each jacket having one end arranged to enterthe coun ter bore of the corresponding clamping ring, and means fordetachably connecting each water jacket to the outer end of itsrespective cylinder.

10. In an internal combustion engine, a cylinder having a dome-like endprovided with only one opening, which is circular and centrallyarranged, the wall of the cylinder being thickened around said openingto form a ring, the wall of the dome comprising two zones, that zonenext to the cylindrical body portion of the cylinder being the zone of asphere and the remainder of the dome being a conoidal zone tangent tothe spherical portion and connecting it with the ring, substantially asdescribed.

11. In a doubleacting internal combustion engine, the combination, witha pair of cylinders, each having a dome-like end provided with a centralopening, the wall of each end being thickened around the opening to forma ring, each dome-like end comprising the zone of a sphere next to thecylindrical body portion of the c linder and a conoidal zone tangent tothe sp ierical zone and connecting it with the corresponding ringportion, of a piston working in both cylinders, a piston-rod connectedto the piston and passing through the central opening of one end, astuflin box secured to the ring around said centra opening for packingthe piston-rod, and a plug inserted in the central opening of the othercylinder, and provided with valve mechanism for the admission of fuel toits cylinder, substantially as described.

12. In a double'acting internal combustion engine, the combination, witha pair of cylinders, each having a dome-like end provided with a centralopening, the wall of each end being thickened around the opening to forma ring, each dome-like end comprising the zone of a sphere next to thecylindrical body portion of the cylinder and a conoidal zone tangent tothe spherical zone and connecting it with the corresponding ringportion, of a piston working in both cylinders, a piston-rod connectedto the piston and passing through the central opening of one end, astuflin box secured to the ring around said centra opening for packingthe piston-rod, a plug inserted in the central opening of the othercylinder and provided with valve mechanism for the admission of fuel toits cylinder, and a fuel valve mechanism for admission of fuel to thecylinder having the stalling box, said fuel valve mechanism beingarranged in the conoidal zone portion.

13. In an internal combustion engine, the combination, with a cylinderhaving an outwardly domed end provided with a central opening, a pistonrod passing through said opening, and a packing gland arranged to packthe opening, of a piston secured to the rod and having an end arrangedto enter the domed end of the cylinder, said end being shaped to form aclearance space in said domed end separated from and closed to thepacking gland to protect the packing gland from the combustion, andmeans secured to the domed end of the cylinder for injecting fuel intosaid clearance space.

14. In an internal combustion engine, the ('()llll)llltlll0ll, with acylinder having a domed end provided with a central opening. a pistonrod passing through said opening, and a packing gland arranged to packthe opening, of a piston secured to the rod and having an end arrangedto enter the domed end of the cylinder, said end being circular in crosssection near the piston rod and near the cylindrical body portion of thepiston and elliptical in cross section at its intermediate portion,whereb a clearance space is formed between this e1 iptical portion andthe domed end of the cylinder, and means for injecting fuel into saidclearance space.

15. In an internal combustion engine, the combination. with a cylinderbase, a frame for supporting the same, a plurality of engine units, eachcomprising a pair of cylinders detachably connected to opposite sides ofthe cylinder base in line with each other, said cylinders havinscavenging air ports within the cylinder liase, a piston for each engineunit working in both of its cylinders, a piston-rod for each piston, amain crankshaft, and connections between each pistonrod and thecrankshaft whereby the shaft is rotated, of a double-acting scavengingairpump comprising two cylinders secured on opposite sides of thecylinder base in line with each other and having the air outlets of thetwo cylinders on the same side of the cylinders, and an air conduitconnected to said air outlet extending along the cylinder base andconnecting to the scavenging air ports of each engine cylinder.

In testimony whereof, I have hereunto set my hand.

OLAV ESKIL JORGENSEN.

